sshhhhshh... trade secret that keeps us employed. At 12:13 PM 09/27/2001 , David Kaiser wrote: >I have a question about LC filters on power SERDES and other Gbit devices. > >Most SERDES venders provide app notes that suggests using LC filters on the >power pins of these Gbit devices to prevent noise from getting on to the >power planes. But it seems to me that the LC filter components would have no >effect at these Gbit frequencies, and could in fact make matter worse >because the power pins would have no more than maybe a small island of >interplane capacitance for decoupling. It seems that it would be better to >just tie the power pins directly to buired capacitance planes. What do the >SI gurus think? > >Also, it seems that at multiple GHz frequencies, the return path for the >noise on the power planes would be so short, that noise would be squelched >to quickly to cause problems on the planes. >------------------------------------------------------------------ >To unsubscribe from si-list: >si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field > >or to administer your membership from a web page, go to: >//www.freelists.org/webpage/si-list > >For help: >si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > >List archives are viewable at: > //www.freelists.org/archives/si-list >or at our remote archives: > http://groups.yahoo.com/group/si-list/messages >Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > ---------------------------- Bill Owsley, owsley@xxxxxxxxx 919) 392-8341 Compliance Engineer Cisco Systems 7025 Kit Creek Road POB 14987 RTP. NC. 27709 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu